Unwinding apparatus



p 27, 1965 o. D. MERRILL, JR 3,275,262

UNWINDING APPARATUS Filed Feb. 28, 1964 FIG.

i -AXIS 0F ROTATION MN @m l5 ,-l6

1/ F1 A I/ All 1A f 28 "1! V .1

II I s2 5| INVENTOR OLONZO D. MERRILL, JR.

BY W

ATTORNEY United States Patent 3,275,262 UNWINDING APPARATUS Olonzo D. Merrill, Jr., Wayne, N.J., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Feb. 28, 1964, Ser. No. 348,212 Claims. (Cl. 242128) This invention relates to a dead spool pay-off apparatus for unwinding light gauge wire at high speeds and closely controlled tension levels.

In the Wire industry, it is customary to package Wire on large supply spools or reels and, in that form, ship the wire to various locations where it is subsequently unwound and processed according to desired end use. Packaging the strand material in this manner greatly facilitates shipping and storage problems; however, most end use processing is a continuous high speed operation where feeding or paying-off the wire, particularly small gauge wire, at low tension levels causes some exceedingly troublesome problems. Ordinarily, elaborate contrivances are required to accomplish this operation with a minimum of tension fluctuations and overfeeding, especially if these variations are to be controlled within close limits.

There are numerous mechanisms in the art which, to a certain extent, attempt to overcome the above difliculties. These fall largely into two categories. The first involves mounting the supply reel on a suitable rotatably driven spindle and with accompanying tension sensing devices, variable speed drivers, clutches and brake mechanisms, paying out the wire in a controlled manner in accordance with the process equipment demands. With this type device, controls must also be provided to compensate for the decreasing mass inertia of the supply reel. Obviously, such apparatus constitute substantial investments, require skilled operators, and involve considerable amounts of maintenance.

The other type of device known to the art unwinds wire from a stationary supply reel or dead spool by means of rotating mechanisms which engage the strand material and revolve around the reel. Although devices of this type are usually less complex, they suffer from the disadvantage of inherent bulkiness and also relatively slow response to sudden tension fluctuations, which causes overfeeding when there is a sudden decrease in wire tension and breakage of the wire when there is a sudden increase in such tension. Additionally, they are best suited at low unwind rates, for at high speeds the wire tends to behave unwieldly and large conical hoods or guide means must be provided to restrain the wire. In some applications this type of restraint cannot be employed due to deleten'ous affects caused by abrasion on the Wires surface.

This invention overcomes the foregoing disadvantages by providing a simple, compact dead spool pay-off apparatus capable of handling a variety of strand sizes and compositions and maintaining the strand at a closely controlled, predetermined tension level, even at speeds of several hundred yards per minute. The apparatus comprises: (a) stationary support means for mating with the vertical bore of said spool, (b) a rotatable hollow shaft supported by, and extending axially through, said sup port means and terminating thereabove in a shaft extension, (c) a platform mounted for rotation with, and reciprocation on, said shaft extension, said platform be ing urged downward by a spring-biased rod extending axially through said shaft, (d) a cantilever arm extending laterally from said platform and carrying 'at its outer extremity a swivelled yoke which rotatably supports a grooved pulley, (e) a lever positioned above said platform and carrying a second grooved pulley at one of its ends and a fulcrum pin at its other end, said lever being pivotally journaled for vertical movement intermediate its ends and adjacent the fulcrum pin in a mounting means fastened to said platform, said fulcrum pin having its tip resting on the top surface of said shaft extension and said second pulley being operatively aligned with said first pulley and rotatable in a vertical plane, and (f) braking means operatively associated with said platform and said support means and responsive to the reciprocation of said platform.

Although the above description and subsequent claims are in terms of an apparatus for removing wire from a vertical spool, it is to be understood that this is merely for the purpose of describing the relative positions of the requisite elements as briefly as possible and is intended to be limiting solely as to such positions. The apparatus of this invention is, in fact, equally useful with an inclined or horizontal spool provided such elements are in the indicated relative positions with respect to each other and the spools axis.

The apparatus is best understood with reference to the appended drawings, in which:

FIGURE 1 is a plan view of a preferred embodiment of the invention;

FIGURE 2 is a cross-sectional elevation view of the apparatus of FIGURE 1; and

FIGURE 3 is a partial elevation view of the fulcrum arrangement of FIGURES 1 and 2.

Turning first to FIGURE 2, a tubular projection, hereinafter described as hub 1, serves as a support for the rest of the device and mates with bore 2 of wire supply reel 3. The reel 3, in turn, is mounted on a fixed capstan (not shown) such that it remains stationary during unwind operations. Base plate 5 is fixedly attached by suitable means to the external end of hub 1 and lies flush against the flange 4 portion of reel 3. The hub 1 is coupled to reel 3 by means of a stud 6, which protrudes from the plate 5 and engages an appropriate hole in flange 4. Concentric with the longitudinal axis of hub 1 and extending its entire length is a hollow shaft 7, which is rotatably journaled on the inner races of antifriction bearings 8 and 9. The bearings are of the conventional type and are fixedly retained in spaced relationship within hub 1 by the interaction of plate 5, tubular spacer 10, and a retainer ring 11. Shaft 7, however, is restrained from longitudinal movement 'by integral shoulder 20 and lock ring 12. The extension of shaft 7, which protrudes through an aperture provided in plate 5, is modified and adapted at its external extremity with a wear surface 13 of some hardened material, such as a :tool steel alloy, and is operatively engaged with the convex tip of a fulcrum pin 14 that is threaded into the extremity of a pivotal lever 15.

As best shown in FIGURES 1 and 3, lever 15 is a gen erally clevis-shaped member having a pair of trunnions' 16 on either side that interfit with suitable openings in a stanchion 17, which functions as a means for supporting the lever relative to the shaft 7. The external end of lever 15, opposite pin 14, is provided with a grooved pulley 18 which is rotatably journaled about a stationary pin 19 that is fixed to the lever end. Stanchion 17 straddles the modified shaft 7 extension and is rigidly connected by conventional threaded fasteners to the top surface of rotatable and vertically reciprocable platform 21.

Referring more particularly to FIGURE 1, platform 21 is essentially a flat surface, supporting at one edge a block 22 and at the opposite edge a weight 26. The free end of cantilever arm 23 is suitably afiixed with a swivelled yoke 24 for rotatably supporting a grooved pulley 25. Pulley 25 and pulley 18 serve as guide means for Wire 33 during unwinding. The fixed end of arm 23 is rigidly held in block 22, and the cantilever arm arrangement is counterbalanced by the weight 26. Mounted to the underside of the platform 21, for rotation therewith, is a flat, smooth-surfaced annular disk 27 which forms a portion of the drag brake arrangement. Spaced opposite this smooth surface, but attached to the stationary base plate 5, is a similar smooth disk 28. Interposed between the smooth surfaces is an annular-shaped drag shoe 29 which is made of conventional asbestos brake lining material. Drag shoe 29 is laterally positioned by annular shoulder 28a and floats freely between the disks utilizing both such surfaces for braking action.

In FIGURE 2 the apparatus is shown in the locked or fully braked position; that is, disks 27 and 28 are shown in contact with drag shoe 29 by virtue of rod 30 and compression spring 32. Rod 30 is concentrically housed Within shaft 7 and is modified by threaded portions at either end so that one end forms a rigid connection with the base of stanchion 17 which is, in turn, fastened to platform 21, while the other end protrudes beyond the inner end of shaft 7 and coaxially accommodates a compression spring 32. One end of spring 32 abuts against an adjustment 31 which is threaded on rod 30 and the other end abuts shaft 7, thereby urging rod 30 in a downward direction. The force exerted by spring 32 may be varied to some extent by adjustment of nut 31, thus providing a simple and convenient means for controlling the degree of braking response and, by that, the tension level at which wire 33 is unwound.

Normally, at zero tension, the apparatus is braked and lever 15 is in the extreme counterclockwise position (as shown in FIGURE 2), and for all practical purposes lever 15 is pivotally resting on trunnions 16. In a preferred embodiment, spring 32 is manually set to yield and release the rotatable platform 21 when the tension on wire 33 is between four and five pounds.

In operation, the leader of wire 33 is passed over pulley 25 and under pulley 18 and thence into the process equipment. Lever 15 responds to a pull exerted on wire 33 by the process equipment by pivoting in the clockwise direction. Since shaft 7 is rigidly fixed longitudinally, lever 15 pivots on pin 14 about a point on the stationary surface 13 and thereby exerts a lifting action on the platform 21 in opposition to spring 32. As the lifting force increases, the force of spring 32 is progressively over-ridden and platform 21 elevates, i.e., it slides up shaft 7, carrying with it the elements fastened thereto whereupon disk 27 becomes disengaged frombrake shoe 29, and platform 21 starts to rotate. During the unwinding operation, platform 21 tends to change its elevation such that on overfeeding lever 15 pivots back in a counterclockwise direction causing the rotating platform 21 to frictionally contact drag shoe 29. Under certain conditions, drag shoe 29 may partially engage disks 27 and 28 for the entire unwind operation in order to maintain a constant tension level. In actual practice, a balance is set up between the tension on wire 33 and the force exerted by spring 32. Any tendency of wire 33 to change its tension level is counteracted by -a movement of lever 15, which may either increase or decrease the pressure on drag shoe 29.

It will be seen that the amount of angular movement made by lever 15 is largely a function of the mechanical advantage of the leverage between fulcrum pin 14, the

ratio (see FIGURE 2) of d (distance between tip pin 14 and axis of trunnions 16) to d (distance between tip of pin 14 and axis of rotation of pulley 18) and thus the leverage may be adjusted by simply fabricating the lever 15 to suitable proportions. A relatively large mechanical advantage permits the use of a larger spring 32 while affording low unwind tensions. The principal advantage derived from the use of such a spring being rapid braking response in the event wire 33 breaks or overfeeds excessively. Of course, a higher mechanical advantage involves larger members and greater angular displacements of lever 15, both of which tend to decrease the compact nature of the apparatus. -A mechanical advantage of about 20 to 1 has been found to provide lever 15 with a reasonable angular movement and satisfactory response to sudden tension fluctuations and, thus, is preferred.

Moreover, the operating range of the apparatus may be greatly extended by substitution of either a heavier or lighter spring 32 for an established leverage ratio. Thus, a single embodiment of the apparatus is capable of handling a variety of wire gauges at any preselected tension level.

From the foregoing, it is seen that the apparatus of this invention is simple, compact, relatively inexpensive and readily adapted for use on multi-line strand handling operations. It is particularly well suited for handling soft wire such as copper without breakage due to sudden tension fluctuations, even at high pay-off rates. Should breakage of the wire occur, e.g., when there is a malfunction in the wire processing equipment, pay-off is stopped immediately by the immediate response of the springbiased braking means thereby preventing further unwinding and resultant entanglement of the wire. The various adjustment features of the apparatus provide it with ex tended capability for processing many kinds of strand material under a variety of tension and speed conditions.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A dead spool pay-off apparatus for unwinding wire at high speeds and closely-controlled tension levels which comprises:

(a) stationary support means for mating with the vertical bore of said spool,

(b) a rotatable hollow shaft supported by, and extending axially through, said support means and terminating thereabove in a shaft extension,

(c) a platform mounted for rotation with, and re ciprocation on, said shaft extension, a rod extending axially through said shaft and having one of its ends attached to said platform, and a spring mounted on the other end of said rod and biasing it and said platform in a downward direction,

((1) a cantilever arm extending laterally from said platform, a swivelled yoke mounted on the outer extremity of the cantilever arm, and a grooved pulley rotatably mounted in said yoke,

(e) a lever positioned above said platform, means fastened to said platform for mounting said lever intermediate its ends, a fulcrum pin mounted at one end of said lever, and a second grooved pulley attached to the other end of the lever, said lever being pivotally journaled, for vertical movement, in said mounting means and adjacent the fulcrum pin, said pin having its tip resting on the top surface of said shaft extension, and said second pulley being operatively aligned with said first pulley and rotatable in a vertical plane, and

(f) braking means operatively associated withsaid pla form and said support means, and responsive to the reciprocation of said platform.

2. The apparatus of claim 1 wherein said braking means comprises an annular drag shoe which is coaxial with said shaft and is interposed between two wear sur- 5 faces which are attached to the bottom of said platform and the top of said support means, respectively.

3. The apparatus of claim 1 wherein the downward force exerted by the spring-biased rod is adjustable.

4. The apparatus of claim 3 wherein said downward force is adjusted so that the platform is released from the braking means when there is a tension of between 4 and 5 pounds on the wire being unwound.

5. The apparatus of claim 1 wherein the ratio of the distance between the axis of the second pulley and the tip of the fulcrum pin to the distance between said tip and the axis of rotation of the lever is about 20 to 1.

References Cited by the Examiner UNITED STATES PATENTS 2,157,847 5/1939 Chapman 242128 FRANK J. COHEN, Plilltlll') Examiner.

MERVIN STEIN, L. D. CHRISTIAN,

Assistant Examiners. 

1. A DEAD SPOOL PAY-OFF APPARATUS FOR UNWINDING WIRE AT HIGH SPEEDS AND CLOSELY CONTROLLED TENSION LEVELS WHICH COMPRISES: (A) STATIONARY SUPPORT MEANS FOR MATING WITH THE VERTICAL BORE OF SAID SPOOL, (B) A ROTATABLE HOLLOW SHAFT SUPPORTED BY, AND EXTENDING AXIALLY THROUGH, SAID SUPPORT MEANS AND TERMINATING THEREABOVE IN A SHAFT EXTENSION, (C) A PLATFORM MOUNTED FOR ROTATION WITH, AND RECIPROCATION ON, SAID SHAFT EXTENSION, A ROD EXTENDING AXIALLY THROUGH SAID SHAFT AND HAVING ONE OF ITS ENDS ATTACHED TO SAID PLATFORM, AND A SPRING MOUNTED ON THE OTHER END OF SAID ROD AND BIASING IT AND SAID PLATFORM IN A DOWNWARD DIRECTION, (D) A CANTILEVER ARM EXTENDING LATERALLY FROM SAID PLATFORM, A SWIVELLED YOKE MOUNTED ON THE OUTER EXTREMITY OF THE CANTILEVER ARM, AND A GROOVED PULLEY ROTATABLY MOUNTED IN SAID YOKE, (E) A LEVER POSITIONED ABOVE SAID PLATFORM, MEANS FASTENED TO SAID PLATFORM FOR MOUNTING SAID LEVER INTERMEDIATE ITS ENDS, A FULCRUM PIN MOUNTED AT ONE END OF SAID LEVER, AND A SECOND GROOVED PULLEY ATTACHED TO THE OTHER END OF THE LEVER, SAID LEVER BEING PIVOTALLY JOURNALED, FOR VERTICAL MOVEMENT, IN SAID MOUNTING MEANS AND ADJACENT THE FULCRUM PIN, SAID PIN HAVING ITS TIP RESTING ON THE TOP SURFACE OF SAID SHAFT EXTENSION, AND SAID SECOND PULLEY BEING OPERATIVELY ALIGNED WITH SAID FIRST PULLEY AND ROTATABLE IN A VERTICAL PLANE, AND (F) BRAKING MEANS OPERATIVELY ASSOCIATED WITH SAID PLATFORM AND SAID SUPPORT MEANS, AND RESPONSIVE TO HE RECIPROCATION OF SAID PLATFORM. 